Trailers used to haul loose materials such as dirt, sand, gravel, or grain commonly have beds or tubs that have an open top with generally vertical front and rear walls and sloping sidewalls for retaining contents within the trailer. Therefore, if the trailer bed is not covered as the trailer is pulled over the road, the loose contents may be blown and scattered out of the open top of the trailer bed. Additionally, the contents of the trailer bed may be compromised by rain, or other contaminants. Accordingly, it is known to deploy tarps across the open top space of the trailer beds to cover the contents of the trailer beds.
Several mechanisms have been devised for deploying the tarps across the trailer bed. Many of these devices include radial arms that are rotatably mounted at the front and rear of the tub and have a roll of tarp disposed between them. As the radial arms rotate in one direction across the truck bed, the roll of tarp between the arms is unrolled to cover the contents of the truck bed. When the arms are rotated back in the opposite direction, the tarp is taken back up upon the roll to uncover the trailer bed. Examples of such devices may be seen in Searfoss, U.S. Pat. No. 6,206,449 and in Michel, U.S. Pat. No. 5,002,328.
Rear dump trailers are able to dump their contents by raising the forward end of the tub and releasing a rear door or flap to permit the contents of the tub to slide out under the bottom of the door or flap. Typically the radial arm of the tarp deploying apparatus will be mounted to the rear door or flap. Therefore, there needs to be flexibility between the radial arm and the tarp roll as the angle between the radial arm and the tarp roll will increase as the rear door is allowed to rotate open during a dumping procedure. One known mechanism for permitting such flexibility is to use a helical spring to form all or part of the radial arm. Unfortunately these springs can be relatively expensive, are somewhat prone to corrosion, and can be dangerous if not properly covered.
Another disadvantage of existing designs results if the motor or other power source for the tarp roll is not functional. Under existing designs, there is no satisfactory mechanism for rolling the tarp up.
Additionally, an improved bracket for mounting radial-arm-type tarp deploying systems is needed that permits flexibility in mounting location and eliminates the need for mounting multiple pieces of the bracket.